6 LESSONS IN POULTRY KEEPING SECOND SERIES. 



What is Inbreeding? 



Inbreeding is breeding from fowls that are ue-\r kin. If the practice is continued through 

 a number of generations it is in-and-in breeding if one wishes to be precise in speech, though 

 common usage tends more and more to the simpler term. 



Inbreeding in fowls extends to unions of the nearest kin sire and daughters, dam and son, 

 brother and sisters. 



Objections to Inbreeding. 



Primarily the objections to inbreeding are based, as has been stated, on social and religious 

 arguments. As these can apply in a question like this only in so far as it can be shown that 

 they affect physical condition we need not enter into them here. It is sufficient to consider the 

 subject solely from the physical standpoint, and as it practically concerns the poultry breeder. 



It is claimed by those who oppose inbreeding that it produces certain and rapid physical 

 deterioration. That it leads inevitably to degeneracy and sterility.' They will admit that by 

 inbreeding some superficial, "fancy" points may be obtained in greater perfection, but claim 

 that inbreeding cannot be carried beyond a very few generations except at the expense of 

 vigor, stamina, size, productiveness, and that if persisted in it leads surely to the extinction of 

 the line. In support of their position they refer to instances cited by early writers of the 

 Darwinian school, to the conclusions of leading investigators of that period, to occasional 

 experiences with or experiments in inbreeding poultry, and to the very evident fact that a 

 great many stocks of pure bred fowls are deficient in stamina and " practical " qualities. The 

 fact that many mongrel stocks on farms and elsewhere which breed indiscriminately; quickly 

 deteriorate is also cited in this connection. 



How the Objections to Inbreeding are Disposed Of. 



First let us take up the points just mentioned in the order in which they have been given. 



Even if the later scientists of the Darwinian school, and some of its leading exponents in 

 these latter days, had maintained the early attitude on inbreeding, it would be pertinent to 

 observe that few of the examples upon which they based their earlier conclusions are of 

 more authority than the ordinary newspaper story of like occurrences', and that none (I 

 believe) will stand such a test as would oe required were they presented today as new evi- 

 dence. 



But, inasmuch as the leading scientists of this school, on further investigation of the 

 subject, concluded that inbreeding did not necessarily lead to bad effects, and modified greatly 

 their earlier views about the advantages of crossing that is, of uniting wholly unrelated or 

 different lines of blood, the reference to their views is chiefly interesting as showing how little 



the condemnation of inbreeding rests upon a careful and thorough investigation of the 

 subject. 



What is said of experiences and experiments in inbreeding merits more attention. As to 

 the experiences : There is no doubt that there have been countless instances where inbred 

 fowls have shown lack of stamina and general deterioration. But we have to take account 

 also of like results where inbreeding is carefully avoided. Any impartial observation cover- 

 ing a great many cases will show tkat these results are so common where inbreeding is 

 avoided as to suggest that the real cause or causes of them must be sought elsewhere. 



Experiments in inbreeding poultry made by those who advise against it have so far as 1 

 have seen the reports of them invariably shown quickly and unmistakably the evil effects 

 they anticipated; but I have never yet seen a report of such experiment which showed that 

 it had been planned with an understanding of what was required to make a test, nor have 

 I ever known an instance where a man who had gone on record in condemnation of inbreeding 

 either attempted to reply to criticism of his experiment which showed where it failed, or 

 by further experiment with conditions corrected attempted to verify his results. That this 

 statement constitutes a severe arraignment of the advocates of what (as far as the numbers 

 who accept it go) is the popular side of an important question, lam well aware; but as a 

 poultryman who, after years of breeding in which inbreeding was carefully avoided, because 

 the weight of authority on poultry culture seemed to lie that way, began to test the matter 



